OPINION:
It is one of the most beautiful sights in a country rich in scenic delights, but it is tarnished.

The river burbling over the greywacke gravel should be clear and sparkling, but it is not.

The water is murky, clouded with sediment. Green algae can be seen floating in it. A brown slime settles on stones at the river's edge, bringing an unpleasant odour. Clouds of sandflies hover.

What has happened? Has a dairy farmer tipped in effluent upstream?

No, the culprit is a state-owned enterprise, power generator Genesis Energy.

It has flushed water from its Moawhango Dam above Waiouru and washed mud and crud down the Moawhango River and into the Rangitikei River.

By the time it gets to Omatane, where I am, the river is murky and smelly. Picnics, camping and fishing will have to wait till another day.

This isn't a one-off. Once a month from December to March, Genesis flushes water at the rate of 30 cubic metres a second for nine hours.

This isn't the company's fault. It is compelled to do so by its resource consent, issued by Horizons Regional Council.

The reason is so the Moawhango River immediately below the dam can be cleansed of a smelly algal and sediment buildup.

I have been asked to Omatane, 45 kilometres from the dam, to see the effect of the flushing. I see the enjoyment of many picturesque riverside sites is ruined.

Farmer Gordon Hammond makes the valid point that if one of his colleagues had been the cause of such pollution, he would have been brought before the courts by the council without delay and named and shamed.

He talks angrily of a double standard, that farmers are being persecuted when other river polluters - big business and local authorities - are not.

To be fair to Genesis, it is just abiding by its consent conditions.

When the Omatane problem was first brought to its attention, it commissioned a hydrologist's report on the pollution.

It said the flushes were probably longer than was needed, but were considerably less than that caused by natural floods.

It also noted that the adverse effects - smelly slime and sediment on the river's edges - would last until the next bigger natural flood, but these are not too common in summer.

That report was three years ago and Genesis has seen no need to change its regime.

Hammond suggests flushing the Moawhango when the Rangitikei has winter and spring natural flushes caused by headwaters rain.

That's a good idea, but Genesis told me such a flush decision would have to be made swiftly and there wouldn't be enough time to warn river users.

I don't accept that. I'm sure something could be worked out if there was a will.

I also asked Horizons about changing the consent conditions to allow flushing at the time of a natural flush. But a spokesperson maintained the Moawhango was most under stress from algae and sediment in summer and wouldn't accept that the cleanout from a spring flush would last through summer, or even allow for only one summer flush.

The Moawhango Dam collects water for the Tongariro power scheme. It is obvious that the dam level has to be high in winter when power usage is high. That could also be a factor in ruling out winter-spring flushes.

Another point is that downstream cropping and dairy farmers draw on the river for irrigation. The summer flushes from Moawhango must help to maintain that.

It all ties in to what is becoming a national dilemma - finding the right balance between the economy and the environment.

Federated Farmers' view is that we can have both economic progress and look after the environment.

But it is a matter of deciding what environmental standards we should stick to. That's the argument we are having.

In her report, Hydroelectricity or Wild Rivers?, Parliamentary Commissioner for the Environment Jan Wright says the Government clearly favours hydro electricity and asks for this imbalance to be redressed.

The Rangitikei is a jewel to be treasured. Its value to our peace of mind, our sense of self-worth, is immeasurable.

It also attracts fishing enthusiasts and adventurers from around the world. We can't tell them, "Come and see our beautiful river, but not in the third week of December, January, February or March."